A guided missile of this sort includes a fuselage or body, with a propulsion system that is usually located in the rear or tail of the fuselage. A pulsed propulsion system can take the form of a solid-propellant or liquid-propellant engine, or a hybrid of the two. Common among them, however, is the need for logical control of the application of propulsive energy throughout the missile's flight. The missile incorporates additional guidance and control functions which produce movement of aerodynamic control surfaces and/or supplemental thrusting subsystem(s) to direct the course of the missile.
There is a desire to improve the performance of such a missile by increasing its speed, range and maneuverability. For example, a high-energy fuel is utilized, and outward characteristics of the fuselage are designed to minimize drag which slows the missile. Likewise, the path the missile is commanded to take towards its destination is engineered to minimize effects of gravitational pull and adverse tracking phenomena associated with the target tracking technology (e.g. radar, infrared, etc.) employed. Control of on-board sub-systems must be accomplished by electronic assemblies which conform to stringent weight, volume and power requirements and through the use of extremely efficient software which does not unduly load on-board data processing equipment, also designed within tight requirement constraints.
There exists, within the art of guided missile design, a goal of optimizing various "kinematic" performance criteria, within the constraints presented by physical aspects of various missile subsystems. In dealing with performance objectives related to most guided missiles, such constraints are typically severe and profoundly influential on the nature of resulting missile designs. For example, propulsive energy available at different times in a missile's flight is heavily linked to the allocated volume and mass property limits in which a propulsion designer is allowed to work. Various known techniques exist within this discipline to enhance and optimize propulsive output within volumetric and weight constraints associated with guided missile airframe designs; among them are the use of high-energy propellant chemical formulations and specifically-tailored propellant grain geometries.
Another technique that has the potential of contributing to enhanced kinematic performance involves the use of various motor design techniques of producing sequential and separate increments of motor thrust output, which will be referred to herein as a "pulsed motor" or "pulsed motor technology," such as described, for example in U.S. Pat. Nos. 3,973,499, 4,085,584 and 4,999,997. This may be accomplished through solid-propellant motor designs with physically separated propellant grains or through other means.
In solid-propellant rocket motors, such approaches allow for short duration, high pressure combustion of propellants which tends to maximize performance output achieved by a given mass of propellant. Such techniques allow for selective release of propulsive energy at optimum points along a missile's flight trajectory, so as to allow desirable guidance and/or control performance in the various phases of target acquisition, tracking and terminal homing of the missile on its intended target.
A problem, however, has traditionally existed in the implementation of pulsed motor technology in guided missiles. The numerous variables involved in the characterization of specific tactical scenarios (e.g. launcher and target locations, velocities and post-launch maneuvers) contribute to enormously complex physical relationships, which are further complicated by varying uncertainties in associated measurements of these factors. Even if the physical relationships were well understood, the implementation must contend with the infinite number of combinations of variables. Indeed, while pulsed motor technology would seem to be well-suited to the challenges of guided missile design, its use has been severely limited by a lack of means by which pulse timing may be optimized for widely-varying launch/engagement criteria. Fixing the timing of sequential motor pulses may produce very effective performance in some tactical scenarios, but is likely to produce lackluster performance in others. A need for scenario-specific control of such motors is thus critical to their effective utilization.
No known pulsed motor tactical air-to-air or air intercept missiles exist today. As stated above, pulsed motor tactical missiles have not been produced because, among other things, no suitable method for controlling the pulse had been identified. There is, therefore, a need for a missile having improved performance obtainable through sequentially-pulsed -motor technology with adaptable control of motor pulse timing as appropriate for optimal achievement of multiple performance objectives specific to each tactical situation. The neural network control device embodied in this invention accomplishes this function, making system implementation of pulsed motor technology in guided missiles an achievable feat.